Cold Snare Cut Versus Avulsion for Colonic Mucosal Resection: A Randomized Ex Vivo Porcine Study (the CONVINCE Study)

Background and Aims

Cold snare polypectomy can only be used for en-bloc resection of small lesions. We describe a new technique, cold snare avulsion, where a cold snare is closed tightly, and traction, at times with substantial force, is applied to resect the ensnared tissue. We aimed to determine the feasibility and safety for lesions up to 15 mm.

Methods

A randomized study in ex-vivo porcine colons comparing en-bloc resection (successful mucosal entrapment and resection in one piece) and perforation rate for cold snare cut vs cold snare avulsion for lesions (1) 10 mm without submucosal injection, (2) 10 mm with submucosal injection, and (3) 15 mm with submucosal injection. Mucosal defects were endoscopically examined, and full-thickness punch biopsies were performed to determine histological depth and completeness of resection.

Results

For 10-mm lesions without submucosal injection, en-bloc resection occurred in 1 of 15 (6.7%) with cold snare cut vs 10 of 15 (66.7%; P = 0.002) with cold snare avulsion. For 10-mm lesions with submucosal injection, en-bloc resection occurred in 9 of 15 (60%) with cold snare cut vs 14 of 15 (93.3%; P = 0.08) with cold snare avulsion. For 15-mm lesions with submucosal injection, en-bloc resection occurred in 1 of 15 (6.7%) with cold snare cut vs 12 of 14 (85.7%; P < 0.001) with cold snare avulsion. No perforations occurred. Resection to the level of the submucosa was confirmed by histologic analysis of the mucosal defect in all but one case.

Conclusion

In an ex-vivo animal model, cold snare avulsion was superior to cold snare cut for complete en-bloc resection of lesions up to 15 mm, with no adverse outcomes reported.